Eye tracking is a known art of which technologies and methods are described in “Eye Tracking Methodology: Theory and Practice” by Andrew Duchowski, ISBN 978-1-84628-608-7. The book describes various methods known in the art for computing a gazing direction from an image of the eye/s. Other sources that disclose use of eye tracking technology are also available.
One of the main applications of eye tracking devices is to provide the main point of gaze of a user on a display screen or on any other object. In some cases the point of gazed gaze is displayed on such a display screen and in some cases the gaze point location may be used to for other purposes, such as activation of a function.
Typical eye tracking systems for such purposes are designed to track the gaze point on the surface of a display screen with the eye tracker mounted at a fix location on the display (typically bottom-center of the display) and designed to track a user that is at a typical distance of 40-100 cm from the display. Such eye trackers are therefore designed also to track users that are typically 40-100 cm from the eye tracker.
These eye trackers allow users the freedom of motion within the head box of the eye tracker with typical size is 40×40×40 cm3.
In various applications, such as surgical rooms, it is often desired to position the display at a distance larger than 100 cm from the user. Eye trackers that are designed to track a user at maximum 100 cm will not be able to track the user anymore when attached to a display that is further from the user than 100 cm.
There is a long felt need for a system which enables the usage of such eye trackers in situations where the display (or any other observed object) is farther away from the user than the maximum usable distance of the eye tracker from the user. The system of the present invention also enables non-fixed spatial relations between the eye tracker and the display (or the object) so that they can move one relative to the other and still maintain the gaze point tracking on the display screen.
In one example, the system of the present invention is intended to assist a user in a surgical procedure. In some arrangements of surgical environments, the space in the immediate vicinity of the user might be loaded with equipment to a degree that it is desired to move the monitor further away. If the distance between the user and the desired location of the monitor display becomes larger than current typical range of existing eye trackers, proper use of these eye trackers will be impaired.